Glass bulbs have been widely used for incandescent lamps since their initial creation. The process for shaping glass into conventional bulb-shapes (e.g., A19, B10, G25, etc.) and then connecting the bulb to a conventional base (e.g., screw-type base) is well known in the art and has been practiced for over a century.
With the advent of solid state light sources (e.g., light emitting diodes (LEDs)), and their use in lighting applications, particularly retrofit applications, bulbs of materials other than glass have typically been used. For example, plastic is sometimes used in retrofit lamps incorporating solid state light sources. Plastic bulbs reduce the weight of a retrofit lamp, which may be considerable, particularly if the lamp includes a metal or primarily metal thermal management system (i.e., heat sink) to dissipate the large amounts of heat generated by the solid state light source(s) within the lamp. Plastic bulbs may also provide greater design flexibility in comparison with glass bulbs.